Heat bed height anomoly  

Re: Heat bed height anomoly

Peter

Sounds from what you are saying, the nozzle is to high?

Is the Z end stop holder down as far as it can go? I presume you have the glass in place (sorry, silly question...)?

Measure the distance from the top of the X rail holder to the top of the Z motor frame on both sides - they should be within 0.1mm of each other.

Have you assembled the hot-bed holders properly? Screw, washer, bed, washer, nut, captive nut. The captive nut must be pushed into the orange adjuster as far as it will go, nylon end first.

Try the above for starters...

Peter

And yes, you got me out of bed! {not really..}

Re: Heat bed height anomoly

I did not have the glass in place!!! I think everything else is ok. Moved the piece that holds the end stop all the way down the other side as well but I didn't do it yet in the picture.

Re: Heat bed height anomoly

I don't know why the pictures are sideways if I put them in the normal way?

Re: Heat bed height anomoly

OK, Peter. Most important now is cable management/routing. Make sure it is exactly as per the manual, and the printer will work for a very long time.

Peter

P.S. you might want to put a cover on top of the RAMBo housing. I was releasing a part last Sunday; the glass moved, the rear left clip went flying, straight into the RAMBo housing. Shorted between the ATMega pins and live/earth. New board arrives tomorrow...

Re: Heat bed height anomoly

Yeah I have to figure out what I am going to do there. The box that came with it doesn't work that great for some reason. Even thought I did route the cables it still was not going in nice. I am going to make a box for this thing and mount everything external. One thing though is my glass is not straight. It is impossible to level it out really nice. There some sort of trick to this, have to figure it out. I thought the glass was bent. The glass gives it an illusion like its bent. This picture thing is very annoying I don't know why the pictures are being displayed the wrong way.

Re: Heat bed height anomoly

Peter

Toughened glass is almost impossible to be made flat, due to the extreme temperatures involved in the toughening process.

It is best checked with a steel rule; place the edge of the rile from one corner of the glass to the other and if you can slide a piece of regular copy paper underneath then that's about a 0.1mm gap.

Flip the glass over and check the other side; it may be flatter.

Print on the side of the glass with higher corners; the heated bed is usually also slightly uneven with the corners lower than the centre. When clipped together, the glass and bed compensate to an extent.

If, when clipped together, the centre is more than 0.1mm higher than the corners, put some insulated packing between glass and clips; bare in mind the amount of heat generated.

Peter

Re: Heat bed height anomoly

make sure your y axis is set down all the way into the prusa frame before tightening the m10 nuts.

Re: Heat bed height anomoly

I spent a long time adjusting the table. It is very tedious task to say the least. It is a high precision move. I was totally convinced that the glass was bent but it was not. What I did was I left 2 opposite corners crossway floating, I took up the adjustment up. Each time I made a move I had to check the adjustment screws because they catch sometimes so I had to seat them sometimes. Then I adjusted the other corners. I used a perfect business card not bent at all. I layed it on the table and set the clearance no bend in the card just flat on the table. If the edge of the card gets bent of messed up it will make a high spot, So the card must remain perfect. I had to go back and forth like 10 times making tiny adjustments until perfect or as close to perfect as possible. I would recommend using a feeler gauge like for automotive industry. These you can bend no problem and the end will not deform like a piece of paper. After setting the first 2 I went to the other corners and did the same. It is a good idea to go back and forth from opposite corners. It takes a very long time to get just right but worth it to get a really good print. One strange thing I found was that if you move the axis and the motors turn they create a voltage. It glitched out my lcd screen a few times while I was making the adjustments. Had to turn on and off to regain lcd display. With the machine off if you move the motors my lcd lights up until I stop moving the motor.

Drum roll please.,,,,, Here is the result my second print ever! not to bad at all. I messed up the corner a bit trying to get it off the table and there is a tiny defect on the bottom but not to big. I was very happy and impressed with the result.

Re: Heat bed height anomoly

Hi Peter

Well done. Don't worry, the calibration gets easier every time. Takes just a few seconds when you get used to it.

When lowering the bed, I always push the screws down (habit). I always level the front, then the right hand side and finally the back, then a quick check over the 4 corners again.

Yes the LCD does glitch due to the voltage generated by the motors. My solution is to press the LCD button twice - once to go into the first menu and once to return. First press refreshes the display.

Peter